Semiconductor integrated circuits are being miniaturized and integrated. As a pattern formation technology which is one of the fine processing technologies for realizing the miniaturization and the integration, there is given a photolithography process. In recent years, the precision of semiconductor integrated circuits has been increased through use of the photolithography process. However, as the processing precision to be required is approaching a diffraction limit of exposure light, the photolithography technology is also coming close to a limit. Then, as a method of realizing further miniaturization and higher precision, a nano-imprint method has been proposed. The nano-imprint method involves applying a resin to be cured with heat or light to a substrate to form a thin film, pressing a mold having a fine depressed and projected pattern onto the thin film, and irradiating the thin film with light or subjecting the thin film to a heat treatment, thereby forming a resin with the depressed and projected pattern of the mold transferred thereto. Note that, as a method of curing a thin film formed on a substrate, there are given a radiation curing method using a radiation such as light, a thermal curing method using heat, and the like.
Incidentally, the nano-imprint method has various problems to be solved while being capable of forming a resin having a fine pattern. One of the problems resides in that a force required for releasing a mold from a cured resin, that is, a mold release force is large. When the mold release force is large, there arise problems such as the occurrence of pattern defects and the degradation in positioning accuracy caused by lifting up of a substrate from a stage.
Under the above-mentioned circumstances, there have been several proposals for solving the above-mentioned problems. For example, Patent Literature 1 proposes a procedure in which a gas generating agent for generating a gas with light or heat is contained in a curable resin. This procedure reduces a mold release force by generating a gas from the curable resin. Further, Patent Literature 2 proposes a procedure for reducing a mold release force by using a photocurable resin which generates a gas with light; and changing a generation amount of a gas through use of a light irradiation amount and pressure to be applied to the photocurable resin. Further, Patent Literature 3 discloses an imprint apparatus capable of reducing pattern defects by applying, when releasing a resist from a mold, a mold release force to the mold in advance to reduce a variation in the mold release force.